There's an old saying that goes, "A man isn't bad, a woman won't love him." Of course, this kind of 'bad' doesn't refer to despicable morals but to breaking away from the traditional image of a good man—being dominant, understanding humor, yet cold, and so on. Such traits often make a guy extremely attractive to girls.
Yusuf Zuck was just that kind of bad boy. Being with him, one could feel an unconventional dominance that everyone around him could sense. Even with this dominant aura, he didn't lack integrity.
He was the type of man who seemed very bad, seemingly unrestrained, yet was full of a sense of justice and strength.
Whether it was Ruth Wilcox or Ember Vance, or even the rich girl Mia, when they were with him, they could all clearly sense his uniqueness.
And it was this uniqueness of his that made people overwhelmingly fond of him.
Ember Vance found herself unable to break away. She might have known what she was doing, yet also didn't because she was already confused.